Amino alcohols are used in various industries, often as minor constituents of compounds to modify the properties of the compound. Generally, they are considered to be safe, but they have been known to cause local skin irritation at higher concentrations in solutions. We report on three cases of occupational asthma caused by ethanolamines: two metal workers exposed to a cutting fluid containing triethanolamine, and one cleaner exposed to a detergent containing monoethanolamine. The diagnosis was based on work-related symptoms and on a chamber challenge with the suspected agent. Persistence of the symptoms after exposure ended was a common feature of the three cases.