May be harmful if inhaled or swallowed

In the book “The World of _____” by Bennett Alan Weinberg and Bonnie K Bealer, there is a photograph of a label from a jar of pharmaceutical-grade crystals. It reads:

“WARNING: MAY BE HARMFUL IF INHALED OR SWALLOWED. HAS CAUSED MUTAGENIC AND REPRODUCTIVE EFFECTS IN LABORATORY ANIMALS. INHALATION CAUSES RAPID HEART RATE, EXCITEMENT, DIZZINESS, PAIN, COLLAPSE, HYPOTENSION, FEVER, SHORTNESS OF BREATH. MAY CAUSE HEADACHE, INSOMNIA, VOMITING, STOMACH PAIN, COLLAPSE AND CONVULSIONS.”

Fill in the blank.

Answer: (select the text below to show)

Caffeine.

Question by Amit Varma