Weak Stomach

Any time you eat or drink anything, including potions, you must succeed a fortitude save (DC 15) or be forced to vomit, losing all beneficial effects of the consumed item; you become nauseated for 1d4 rounds, even if the save is successful. Furthermore, you have a −2 penalty to all fortitude saves, as a result of your troubles.

Roleplaying Ideas: Characters with this flaw struggle to keep their food down, and appear weak and malnourished. They often have to stock large amounts of extra food in order to survive.

You simply cannot hold food and drink down, resulting in a frail, often malnourished character.