Chlorobutanol (trichloro-2-methyl-2-propanol) is an organic compound with the formula CCl3C(OH)(CH3)2. It is a halohydrin—specifically a chlorohydrin. Chlorobutanol acts as a preservative, sedative, hypnotic, and weak local anesthetic similar in nature to chloral hydrate; it also has antibacterial and antifungal properties. Chlorobutanol is typically used at a concentration of 0.5% where it lends long term stability to multi-ingredient formulations. However, it retains antimicrobial activity at 0.05% in water. Chlorobutanol has been used in the anesthesia and euthanasia of aquatic invertebrates and various fishes. It is a white, volatile solid with a camphor-like odor.