The morphological structure of the seeds of four species of the genus Corydalis Vent. from the family Fumariaceae DC. which are valuable as a source of drugs possessing hypnotic, sedative effect and in small doses are used in neurology and psychiatry. A comparative analysis of morphological features of seeds of four species of the genus Corydalis selected the most stable carpological traits: seed size; the character of hilum and availability of tubercle over it; sculpture of the surface; configuration and color of caruncles. These characters can be used as additional diagnostic criteria for the identification of taxa and herbal medicinal raw materials.