Effects of Chinese herb, Huang Chin (Scutellaria baicalensis George) on thermoregulation in rats.

Intragastric administration of a Chinese herb, Huang Chin extract (Scutellaria baicalensis George), produced a dose-dependent fall in rectal temperature in conscious rats in a room the temperature of which was 22 degrees C or below. The hypothermia in response to Huang Chin application was brought about solely by cutaneous vasodilatation (as estimated by an increase in cutaneous temperatures). There were no changes in either metabolic heat production or respiratory evaporative heat loss. However, in the heat (29 degrees C), Huang Chin administration produced no changes in rectal temperature or other thermoregulatory responses. The data indicate that Huang Chin extract produces peripheral vasodilatation which leads to a hypothermia in conscious rats.