Over the years of dealing with my skin woes, I’ve learned a very important thing: Inflammation is behind a ton of conditions, from rogue breakouts to things like rosacea. Usually, said inflammation starts in the gut, which means that while skin is a giveaway that something could be up with the microbiome, so too, are conditions like constipation and diarrhea. In other words: If you suspect something is up with your microbiome, look to your skin and your stools for validation.

When you think about it, though, your entire body sends signals to you about what’s going on beneath the surface. “Digestion is the root of all health—something that Ayurveda has known for thousands of years,” says Jessa Blades, herbalist and natural beauty and wellness expert. “A healthy body means having ways to get rid of waste and toxins through different pathways: kidneys and urine, skin and sweat, and through bile and the intestines.”

Since everything’s so incredibly connected, I’m taking a deep dive into the two biggest indicators that something’s up with your gut: your skin and your stools.

So what’s up with the skin-gut connection?

For starters, a little biology refresher: “Your gastrointestinal tract, or digestive system, runs from your mouth to your anus and includes your stomach and intestines,” explains Niket Sonpal, MD, a New York-based internist and gastroenterologist. “It’s responsible for not only breaking down your foods, but also absorbing the nutrients from that food and filtering any waste products or toxins out of your body.” Those nutrients are the building blocks of cells, including skin.

You’ll be able to tell if your body’s not absorbing these nutrients if you have chronic, oily diarrhea: “This is a sign your small intestines are not absorbing nutrients for a variety of reasons,” he explains. “Finding undigested food in your stool once in a while is normal, however, when it becomes chronic you may wonder if you’re having malabsorption or not chewing sufficiently.” Improper absorption of nutrients can also display on skin, according to Dr. Sonpal. “For example, zinc deficiency can cause a type of dermatitis while vitamin C deficiency can lead to breaks in the skin.”

The skin-gut connection is also important because the gut is home to trillions of different strains of bacteria, which maintain homeostasis in the body and skin, he says. “They can also release chemicals that can be associated with conditions like acne, atopic dermatitis, and even eczema,” he adds.

Mona Dan, acupuncturist, herbalist, Traditional Chinese Medicine expert, and Vie Healing founder, agrees, emphasizing the importance of the gut microbiome. “Research shows your overall gut microbiome is reflected in having a normal, daily bowel movement, or it shows that it’s unhealthy if you’re having diarrhea or constipation,” she says. “When you have either extreme, you can make the assumption that your gut microbiome is off—which can be a contributing factor to skin problems.” She also notes, however, that association isn’t fully the causation, and that research suggests inflammatory skin concerns are linked with dysbiosis.

How do different stool types indicate the state of your skin?

So, yes—for the sake of your skin, you want to have healthy number twos. “Regular, normal bowel movements are an indication that your systems are working optimally,” says Adarsh Vijay Mudgil, MD, medical director of Mudgil Dermatology. “Having bowel movements daily is ideal, though there is natural variation. Constipation or diarrhea can cause a significant imbalance within your body, including your skin.”

Take a glance at the Bristol stool scale to identify what your poop’s telling you and whether it’s considered healthy. “Typically, with people dealing with constipation, you’ll see a dull, more dry complexion due to the lack of hydration in the body,” says Dan of the Traditional Chinese Medicine understanding of the bowel movement-skin connection. While there’s no study to back this up, considering that dehydration is frequently a marker of constipation, it makes sense that the rest of the body (and complexion) could be parched as well.

If you’re dealing with loose stools, on the other hand, that can show up in the opposite way on your skin. Someone dealing with loose stools may have indications of dampness (another TCM philosophy), which can manifest on the skin in the form of oiliness. “It all comes down to hydration, or the amount of fluid the body is able to hold onto,” says Dan. “It can show in your pores—you may notice that it looks like your pores can’t hold onto fluids and you’ll see an unhealthy oily look.”

What’s the game plan for a healthy gut?

Ok, so to get things clear on skin and stools, the name of the game is hydration. “Keeping the body hydrated enough so that it doesn’t have to hold onto excess damp materials is key,” says Dan. “Your cells, your body, and your gut microbiome thrive on water.” Proper hydration is also key for healthy skin because drinking water helps your body to flush out toxins and keep fluids circulating through the body.

Chances are, you may already be on the probiotics train—but if not, it’s also good to help with your bowels. “Probiotics are essentially beneficial bacteria that can exert positive effects on your gut as well as your skin as they are passing through,” says Dan, who recommends eating sauerkraut and kimchi. “They can also attach and colonize to increase your beneficial bacteria load and diversity as well as crowd out harmful bacteria.” Topically, fermented beauty products can help since they’re more bioavailable for your skin and also contain healthy bacteria.

As far as your diet goes, keep it greens-heavy and full of fiber. “Feed your microbiome with fiber, so eat an abundance of fruits and vegetables—which will also provide a good dose of polyphenols and keep things moving along,” says Blades, who adds that you should try and cut your sugar intake since it feeds the bad bacteria in your gut (it’s also not great for skin, sadly). In short, by working backwards from the gut, you can decipher what’s happening and as a result have a whole happy system moving things along.