At some point over the last few years – or last few days, depending on your social circles – you've probably heard about detoxing and cleansing. Some websites use these terms interchangeably; they're marketing words meant to indicate whatever it is the company is trying to sell. Others have more defined uses for the terms.
So what's the difference between them?
The Original Detox
The process of detoxification originally referred to drug or substance abuse. Addictive drugs and alcohol make changes to your body and force you to crave more of them, often times coupling with resistance that leads to higher and higher doses until you're reaching dangerous levels. 
Going cold turkey with many of these substances is dangerous itself. In fact, once you've done a particular drug for long enough, it's possible that your body adjusts to actually depend on it. Withdrawal can be harmful and in some cases even deadly. Long-time, high-level alcohol abuse is one prominent case; quitting cold turkey can kill you.
The original detoxification is a category of processes and support networks that help a person wean themselves off of their abused substance and try to restore some level of balance in a natural lifestyle. This might mean forcing them to go cold turkey and simply restraining them while the withdrawal runs its course. It might mean weaning them off gradually and replacing their cravings with healthier options and a social support network that assists in resisting the cravings that result.
Regardless, this original form and definition of detoxification is not what we refer to today as a detox. Or, rather, it is, but only in reference to substance abuse. In health foods, supplements, and natural healing, a detox is something else. The only similarity is that a detox is meant to purge the body of toxins. It's just that in the original definition, the toxins were alcohol or drugs, while in the health detox the toxins are things like heavy metals and environmental poisons.
The Healing Detox
A healing detox, health detox, or natural detox is a complex and varied set of processes. There's a lot to cover, so bear with us.
Modern living is full of exposure to toxins. These toxins are in the air we breathe, in the water we drink, and in the food we eat. We are constantly exposed to them. They include things like plastics in our water, heavy metals in our food, unnatural preservatives, the various artificial dyes found in many foods, and so on. 
Many of these chemicals are harmful to the body in large amounts. "That's fine though, right? You're not going to be eating large amounts of them." Well, that's not really true. These toxins might only be present in small amounts, but they're present in just about everything we eat. You might not get a fully dangerous dose from any one source, but you're getting them from dozens of sources every day.
This can be worse depending on your diet and even where you live. Living in a large city like New York or Los Angeles exposes you to a lot of airborne pollutants you might not encounter in a more rural area. Living in an area prone to wildfires can expose you to dangerous particles in smoke-laden air. Living near a polluted water source might mean your groundwater is contaminated. You know all of that outcry over high lead levels in Flint, MI? The same story is playing out in thousands of cities in the country.
There are immense amounts of contaminants all throughout the country, largely as a byproduct of industrialization and modernization, where businesses care more for their short-term profits than they do about long-term health for their customers, their workers, or their environment.
Now, your body isn't wholly helpless in the face of these environmental toxins. In fact, you have a fairly well-developed system in place in your body already meant for purging toxins from your system. Your digestive and circulatory systems carry good nutrients to your cells, but they also circulate the bad, unusable elements back. 
Your liver is the organ primarily responsible for this processing and detoxification, with some help from your kidneys. It's a very resilient organ that filters crap out of your blood, isolates it, and purges it. It is purged through urine, feces, sweat, and even through your breath.
The liver isn't perfect, however. There's only so much it can do. After all, the liver evolved to fight off environmental toxins found in things like slightly poisonous plants or water with some unhealthy minerals in it. It wasn't designed to fight off the smog produced by a coal plant, the lead being eroded into your drinking water, or the heavy metals found in ocean fish.
Over time, higher levels of exposure damage your liver. The liver can heal quite effectively, but it's not immortal. Some damage becomes lasting, which leads to issues like fatty liver disease, cirrhosis, and cancer.
Have you pieced together where this is going?
The health detox process is a system that takes advantage of your existing liver and detox processes. It uses supplements to enhance liver function, changes your diet and activity levels to minimize intake of environmental toxins, and encourages your body to purge existing toxins. 
The idea is that, even though these toxins build up over time, doesn't mean they're stuck there forever. Some are, unfortunately, and there's nothing we can do about it. Most, though, can be purged if you give your body the chance and the tools necessary to do it. That's what the modern detox is about.
So, a health detox uses supplements, dietary changes, exercise, and occasional additional tools to bolster liver function and free up toxins within your body to allow them to be purged. It's often meant to be the start of some lifestyle changes, such as keeping up an exercise routine or making changes to your diet that last indefinitely.
So What Is A Cleanse?
Some people use the term cleanse to refer to the health detox, but it's not actually the same thing. A cleanse is more of a short-term process meant to shake out and wake up your body.
The goal of a cleanse is similar to the goal of a detox, but they don't work in the same way. A cleans aims to remove toxins, yes, but it doesn't do it by boosting the liver. Instead, it does it by purging your digestive tract as much as possible.
In addition to toxins, a cleanse aims to remove everything from fecal matter to parasites and fungi stuck in your system. It can also help to purge unhealthy gut bacteria and replace them with healthier bacteria. Note that you can never completely remove gut bacteria, and if you did, your digestion would suffer immediately. In fact, there is increasing evidence that a healthy gut biome is crucial for everything from your immune system to your brain function and beyond.
One thing to mention is that many people tend to associate the idea of a cleanse with the idea of fasting. Fasting requires you to minimize caloric intake to such a low level that your body is forced to burn stored fat for energy. It's essentially controlled, short-term starvation.
A cleanse is different. A cleanse focuses on a liquid diet, but it uses robust ingredients like fruits and vegetables to provide nutrients to your body. You don't starve yourself with a cleanse, you simply eliminate solid foods for a short time.
This is another difference between a detox and a cleanse. Some detox processes involve supplements that you can take indefinitely, on an ongoing basis. Some are harsh, of course, and limit you to only 2-4 weeks of detoxing before you return to a healthier lifestyle. A cleanse is almost always short term, often lasting for only 3-7 days.
During a cleanse, a primarily or all-liquid diet leaves your body lacking solid food. This forces you to purge out any lingering solids in your digestive system. We're not going to lie here; it's often somewhat unpleasant, and you may end up spending quite a bit of time in the restroom.
Cleanses also force you to pay attention to the foods you eat. Once you've "reset" your body with a cleanse, you may find that you have lost your taste for certain artificial ingredients. A cleanse is often the first step to cutting out processed white flour or processed sugars, high fructose corn syrup, or preservatives from your diet.
Different kinds of cleanses work differently, as well. Juice cleanses rely on fresh juice and smoothies to provide you with nutrients. Other kinds of cleanses allow you to eat some solid foods, so long as they're healthy and nutrient-dense. The one commonality is that they all tend to cut out unhealthy processed foods, preservatives, and sugars from your diet.
The goal of a cleanse is not really to remove toxins. Your body already does that, and a short-term cleanse isn't going to do too much to help. A cleanse is meant to even out and "reset" your digestive system, purge out any lingering nutritional issues, and help you embark on a quest of removing processed sugars and refined ingredients from your diet.
But What About…?
We know a lot of you have questions, and we encourage you to leave those questions in the comments below. First, though, let's answer a few of the common questions.
Can you do both a detox and a cleanse at the same time? Sure. They're similar enough that they're often complimentary, though you may feel extra unpleasant for a short time while you're processing them both.
A cleanse simply focuses more on your diet, while a detox focuses on boosting your natural bodily functions. You can think about it like cleaning your house. A cleanse has you vacuum your floors to remove dust, while a detox has you installing (or cleaning) an air filter to help remove the dust before it settles on your floor.
What about X? There are a lot of different people out in the world selling you different detoxes and cleanses. The definitions above are simply our preferred definitions, and are aimed at drawing a tangible distinction between the two processes. There are businesses out there that label their products as a "detox cleanse" or who even flip the definitions on their heads. Some of them call a cleanse a deeper, more intrusive version of a detox.
The reality is, there's no truly clear definition, because everyone kind of makes their own. We've tried to create definitions based on mechanisms on how each process functions, but there's a lot of overlap.
Regardless of the definition you use, both a detox and a cleanse are aimed at the same eventual end goal. They work to help you cut out processed foods, sugars, and other artificial ingredients that aren't healthy for your body. They work to help your body purge out any lingering toxins, from heavy metals to plastics to sugar to other contaminants. They work to adjust your body to feel awful when you consume more of those, so you're less likely to fall into old habits.
At the end of the day, both processes are meant to assist your body with maintaining its health, healing from existing damage, and resisting future damage. As long as you use them as a jumping off point for healthy habits and diets, rather than one-shot cure-alls, you should be just fine.
