Doctor Balthus was a female botanist stationed on board the USS Enterprise-D during the 2360s.

In 2367, Balthus wanted Keiko O'Brien to do a study on the laticifer ontogeny of Kaladian thorn flowers, but Keiko was too busy with other projects. Keiko explained Balthus' request to her husband Miles as the reason she was late getting back to their quarters. (TNG: "Night Terrors")

This character was only mentioned in dialogue.