The effects of histamine on contraction of rabbit taenia coli were studied. The results obtained were as follows: 1) The contractile response to histamine was appeared at the concentration of 10^-7M and increased in a dose-dependent manner to the concentration of 10^-4M. 2) The magnitude of the histamine-induced contractile response was declined during short-term exposure in rabbit taenia coli. After 40-min exposure to histamine, the contractile response did not altered. 3) Histamine-induced contraction was not influenced by hexamethonium(10^-4M), propranolol(10^-4M) and phenoxybenzamine(10^-6M). 4) H₁-receptor blockade such as chlorpheniramine(10^-6M) and pyrilamine(10^-6M) completely abolished the response of the taenia coli to exogenous histamine, while H₂-receptor blockade (cimetidine, 10^-6M) did not alter. 5) After the treatment of verapamil the histamine-induced contraction was significantly inhibited, but in the treatment of 2 mM La³⁺ it was not influenced. 6) In the absence of Ca²⁺, histamine induced contraction in the different manner of acetylcholine. When taenia coli war treated with atropine(10^-6M) which was completely blocked the contraction by acetylcholine(10^-4M), histamine-induced contraction was not altered. These results suggest that in the rabbit taenia coli exogenous histamine induced contraction through H₁-receptor, but not through the mechanism of acetylcholine.