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Pippali (Piper longum) and the classical combination Trikatu (Pippali, Maricha and Shunthi) are added to many Ayurvedic formulations, and modern authors often describe them as bioenhancers in line with the classical idea of yogavahi, a substance that carries and amplifies the effect of what it is combined with. Piperine, the principal alkaloid of long and black pepper, has been studied for this property since the 1980s. This review traces the concept from classical texts to modern pharmacology and appraises the human evidence. Mechanistic studies show that piperine inhibits hepatic drug metabolism, the efflux transporter P-glycoprotein and the enzyme CYP3A4. In healthy volunteers, piperine increased exposure to phenytoin, propranolol and theophylline. A small study reported a 2000% increase in curcumin bioavailability with 20 mg of piperine, but that figure rested on a curcumin-only control below the detection limit, and a larger crossover trial found no significant advantage of a piperine formulation over a standard extract. Piperine also enhanced rifampicin activity against Mycobacterium tuberculosis in vitro, but its clinical value as an adjunct remains unproven. The evidence supports the classical intuition that pepper alters what accompanies it, but the effect is variable, depends on the co-administered substance, and is not selective, so the same mechanism that enhances an herbal drug can raise levels of a conventional drug with a narrow therapeutic index. We propose that Ayurvedic bioenhancement be studied with whole classical preparations, realistic doses and formal pharmacokinetic designs.