Summary. An in-vitro perivascular nerve-muscle preparation of the human Fallopian tube was studied to assess the potency of various adrenergic blocking agents and beta-receptor stimulants. The administration of alpha-blocking agents, i.e. phenoxybenzamine, phentolamine, tolazoline, yohimbine and hydergine depressed and sometimes reversed the contractile response to nerve stimulation (sympathetic reversal) while the contractile response to noradrenaline was always changed to relaxation following treatment with these drugs. After pre-treatment with alpha-blocking drugs, the inhibitory responses to nerve stimulation and noradrenaline were strongly depressed or abolished by beta-blocking agents, i.e. propranolol and dichloroisoprenaline. Unexpectedly, the contractile response to nerve stimulation was gradually depressed when using the beta-blocking agent, propranolol, alone whereas the contraction in response to noradrenaline was augmented by this drug. The administration of various beta-receptor stimulants always caused a decrease of muscle tone. The inhibitory activity increased in the following order: Du21220, adrenaline in the presence of phenoxybenzamine, isoprenaline and Cc-25. The inhibitory effect of the beta-stimulants was strongly depressed after pre-treatment with propranolol and dichloroisoprenaline. The blocking potency of propranolol was more marked than that of dichloroisoprenaline. The isthmus region of the tube was more sensitive to autonomic agents and nerve stimulation than the ampulla. This suggests the isthmus acts as a sphincter.