There are a few different reasons. Some medications cause gastric irritation as described well in the thread. Some medications work better if their absorption is slowed down a little, and food can do this. Paradoxically, some medications are absorbed more completely with food. An example of this is lurasidone (Latuda), used in bipolar disorder, which needs to be taken with food for absorption to be complete.
As others have stated, it’s because some meds stimulate acid production and can damage your stomach/intestines.
Anecdote: I was prescribed Diclofenac for pain management, back when I was working a job where I couldn’t risk getting/being high while on shift.
The doc was a really down-to-earth type, so when he was going over the side effects and warnings, he had a *very memorable* way to emphasize that you have to take it with food:
“You cannot take Diclofenac on an empty stomach. If you take this without food in your stomach, it will mess you up. ***You will shit blood for several days***. I don’t want to get a call from you in a week saying ‘doc, there’s something wrong! I’m shittin blood!’ It’ll be because you forgot to eat before taking your meds.”
With a few exceptions (like NSAIDs) often patients are told to take with food for psychological reasons. If it’s SO POWERFUL it will burn your stomach out then it must be strong stuff and bound to work better then namby pamby paracetamol.
Source: working in A&E. Especially for our “regular” patients, giving complicated instructions on how to take a medicine (whilst remaining within BNF dosing guidance) greatly increases the effectiveness any meds they are given. Having to take with food or it being very important that meds are taken at exact times are commonly used.
Some medicines are not water soluble, so some foods can cause interference.
Some foods (like grapefruit) affect absorption rates.
Some foods contain amplifying/neutralizing chemicals. For example, leafy greens contain a ton of vitamin K, which can amplify the effect of blood thinners to undesired levels.
Your stomach has 2 sphincters: the oesophageal sphincter (which connects the oesophagus and the stomach) and the pyloric sphincter (which connects the stomach to your small intestine)
When you are in a state of fasting, your oesophageal sphincter is closed to keep from having acid reflux and your pyloric sphincter is open (well more relaxed).
When you eat something it stimulates you stomach. Which means it relaxes the oesophageal sphincter and closes off the pyloric sphincter. Which will give the medicine dissolve in the gastric acid. And it will pass slower to the small intestine where it will be absorbed.
Latest Answers