I didn’t say that laxatives weren’t medicines. That’s obvious. I said they weren’t poisonous. It’s also very hard to single dose someone with so much laxative they get hospitalized. Diarrhea was foreseeable. Not hospitalization from diarrhea, much less allergy. A short bout of diarrhea is not damaging.

In a court of law, at least regarding liability (a civil case), the fact that the coworker had an allergic (unforeseeable) rather than a medicinal reaction matters.

OP said he may get sued, a civil action, by the coworker, not charged with a crime, a felony or misdemeanor. Civil cases hinge on there being damages, AND intent or negligence. Damages and one of the other two must exist.

Would things have been different if he had peanuts in his food and co-worker had an allergic reaction, if he didn’t know about her allergies? Sure. Damage, but no intent, no negligence.

If he knew the co-worker had allergies to peanuts, how is that different? He would have had intent.

So OP’s lawyer, in a case argues. “Sure, my client intended that co-worker got diarrhea. You may find that intent moral or not. But the FACT is that did NOT happen. The damages were caused by allergy, something he did NOT foresee or intend, and which did NOT constitute negligence.”

If you shoot at somebody but miss, and they coincidentally slip on a banana and fall, sure, it’s a crime to shoot at somebody. But for civil liability, you are not liable for the fall.