Discussions were made on the olfacdtory sense appeared in the dreams. The author also clinically classified the olfactory sense from the view point of illusion and hallucination as follows. Hypersensitive intensification of olfactory sense Diminution of olfactory sense Loss of olfactory sense Fallacious olfactory sense Olfactory illusion Objective maldorous olfactory sense Residual olfactory sense
