A pre-warp planet shared by two humanoid species, the dominant Valakians and the gentler Menk, where Archer and Phlox face a painful choice over a cure in Dear Doctor.
Valakis is the homeworld of two intelligent species. The Valakians run an industrial society and have sent sublight ships into space in search of help, and the Menk live alongside them as a cared-for but subordinate people. The planet appears in the Enterprise episode Dear Doctor, set in 2151.
The Valakians are dying of an epidemic that their doctors cannot stop. Phlox finds that it is not an infection but a genetic decline which will make them extinct within about two centuries. He also finds that the Menk are untouched by it and show signs of growing ability.
Phlox develops a cure but argues that giving it would interfere with the planet's natural course. Archer reluctantly agrees and leaves only medicine to ease the symptoms, a decision often read as a first step towards the Prime Directive.