The color of a tablet or capsule can add a “placebo” boost to the therapeutic effects in real, legitimate drugs.
For example, yellow pills tend to make the most effective antidepressants – like doses of drug-induced sunshine! Green tablets or capsules reduce anxiety – looking out over a plush landscape is soothing, and the dominant verdant color scheme is obvious to us all. And red tablets are associated with a stimulating “kick” and “charged-up” sensation.
The placebo response couldn’t care less whether or not the impetus for someone’s improvement is due to the therapeutic effect of a drug. All it requires is someone with a reasonable expectation of getting better. I’d call that powerful medicine!