Cannabis is an increasingly sought-after remedy for US children with intractable (biomedically uncontrollable) epilepsy. However, like other complementary-alternative medicine (CAM) modalities, and particularly as a federally illegal, stigmatised substance, it is unsanctioned by mainstream medicine. Parents are largely on their own when it comes to learning about, procuring, dispensing, and monitoring treatments. Exploring how they manage is crucial to better assist them. Implications for understanding the boundaries of science are explored, as are norms for parent agency as ill children’s care managers, radicalisation among people affected by contested illnesses, and the future of ‘medical marijuana.’