For 4 months C57 mice were fed a nutritionally complete diet containing 9% alcohol or isocaloric sucrose and killed then or after 4 months recovery on standard food pellets. Electron microscopy was used to count synapses among the cerebellar Purkinje cell dendrites and a significant 13% reduction was found in the alcohol recovery group. The shape of the postsynaptic density material was studied and a significant 11% increase in length found in the alcohol group. The smaller thickness of the postsynaptic material in animals of the alcohol recovery group may be representative of new synaptic formation.