Dear Avery,

I think it’s really cool when a clear pill has teeny tiny balls of medication inside it. My paws itch to bat it around—but I know medicine isn’t a toy, so I sharpen my claws on my desk and then get back to answering your questions.

I asked my friend Damianne Brand-Eubanks what happens after you swallow one of those capsules. She teaches in the College of Pharmacy and Pharmaceutical Sciences at Washington State University. She’s an expert on medication.

She told me that the outside of a pill capsule is usually made of gelatin. That’s the same stuff that’s in jello or gummy candy.

“Just like with food, you swallow the pill, and it goes down the esophagus into the stomach, where there’s a whole bunch of acid,” Brand-Eubanks said. “That acid breaks down the gelatin capsule.”

Once the capsule is broken down, your body will recycle any bits it can use. It will send the rest through your digestive tract with all the other waste that leaves your body.

Dissolving that gelatin capsule releases the medicine inside. The medicine travels to the small intestine and then the liver. Brand-Eubanks says the liver acts like a gate. It can let the medicine through to the bloodstream. Or it can block it from entering and kick it out of the body as waste. Sometimes special proteins in the liver activate a medicine by changing it a little bit.

Some medication comes as a tablet. It won’t have a gelatin shell like a capsule, but it might have a protective coating. That coating prevents the tablet from dissolving in your stomach because that medicine might hurt your stomach. It dissolves once it reaches the small intestine instead.

A gelatin capsule may contain powdered medicine or liquid medicine. The water in your body will immediately turn the powder into a solution so the medicine can travel safely through your body. A tablet feels harder and doesn’t have a gelatin shell around it, but it may have a coating. Images: Sage Ross CC-BY-SA 3.0, Slashme CC-BY-SA 3.0

All those capsules and coatings are designed by scientists to release the medicine in the right place at the right time. That’s why you can’t chew up pills that are meant to be swallowed—unless a pharmacist tells you that’s ok. Chomping up a non-chewable pill could hurt your stomach or make the medicine not work right. Plus, it probably tastes horrible.

Some capsules release medicine very slowly. That capsule can’t dissolve super-fast because it needs to stick around while the medicine gradually does its thing. Those empty capsules can pass through your digestive tract in one piece.

“Sometimes the capsule can come out whole, which can be alarming, but it’s just discarded,” Brand-Eubanks said. “It’s called ghosting because when you go to the bathroom, there’s a little ghost in there.”

I guess I should take a chill pill if I ever see an empty capsule in the litter box. It’s just one of the clever ways scientists have engineered medicine to help us feel better.

Sincerely,

Dr. Universe