Two new species of Cnidoscolus section Calyptrosolen (Euphorbiaceae) are proposed from Mexico. Both are drought deciduous shrubs that occur in tropical deciduous forest and are endemic to the country. Cnidoscolus eglandulatus is known only from the state of Oaxaca. It is noteworthy in lacking a petiolar gland. Cnidoscolus infernidialis is endemic to the state of Michoacán. The conservation statuses of both species were evaluated following IUCN and MER criteria, and they were determined to be critically endangered (unofficially) and endangered, respectively. A key also is provided to identify all of the known Mexican species of Cnidoscolus, which occur in C. sections Jussieuia and Calyptrosolen. Future collectors of the genus are encouraged to describe the petiolar glands when they are fresh, given their importance as diagnostic characters.