I feel like the thing about enhancement magic kinda gave away the secret, didn't it? If enhancement magic makes the sympton worse, then that means the diarrhea symptom is the body reacting to some compound in the fruit, rather than the bad compound itself causing the diarrhea to happen involuntarily. Because enhancement magic would make the body react stronger, meaning worse symptoms.
The solution I estimate would involve something like adding something to the food to neutralize the compound after it gets into the stomach (meaning after it has been tasted), or by temporarily blocking the body's diarrhea response, such as through an anti-allergy medicine. Of course, if the thing in the peach that imparts flavor is separate from the one that causes diarrhea, then you could always find a way to separate those two.
The solution I estimate would involve something like adding something to the food to neutralize the compound after it gets into the stomach (meaning after it has been tasted), or by temporarily blocking the body's diarrhea response, such as through an anti-allergy medicine. Of course, if the thing in the peach that imparts flavor is separate from the one that causes diarrhea, then you could always find a way to separate those two.
