A bear derived isolate found in denning black bears or black bears from which food has been withheld for at least two weeks when injected into another mammal produces reduced heart rate, reduced respiratory rate, reduced temperature, and a wakeful tranquility not unlike the phenomena of the denning black bear. The isolate is taken from either the serum or urine of such denning bear. The method of the invention involves the steps of fractionating the serum or urine of a denning black bear to produce fractions of varying potency.