Deficiencies in cholinergic nerve function have been clearly documented in patients with Alzheimer's disease. The lack of this neurotransmitter may be responsible for early memory loss in patients with the disease. Choline mustard Az ion has been used in our laboratory to produce cholinergic hypofunction in rat brain. Injections of the compound into the medial septal nucleus and dorsal hippocampus produced tissue lesions. The lesions were dose and time-dependent. Lesions produced in the medial septum resulted in transmitter depression in the hippocampus. These results suggest non-specific tissue damage because 5-HT levels were lower than normal. Other strategies for getting choline mustard Az ion into rat brain are being investigated to circumvent the apparent ability of this compound and other nitrogen mustard analogs of choline to produce non-specific tissue damage when injected directly into brain tissue.