Hair tonic
From Tardis Wiki, the free Doctor Who reference
Hair Tonic was a drink available in the 42nd century, used to combat hair loss. Ood Operations chairman Klineman Halpen was a regular user, and this was used against him by his Ood servant Sigma to turn him into an Ood. The tonic was actually Ood graft suspended in a biological compound. (DW: Planet of the Ood)