Allergy

Rachel, from the other end of the office, e-mailed me. She used to work near me and Dan, and knows I carry some hayfever pills around with me, in case I forget to take mine in the morning. Dan used pinch some off me when his hatfever was bad. So the mail read something like:
Rach: "Have you got any allergy pills?"
Me: "What are you allergic to?"
Rach: "HUMANS."