The high and accelerating price of new anticancer drugs is giving rise to increased concern. However, monetary price is not the only way to value chemotherapy. Toxic effects can also be seen as a form of payment in which “units” of wellbeing are exchanged for “units” of efficacy. Although this trading analogy is not perfect, a proposal can be made that toxicity is a type of price, and that one of its functions is to signal valuation, similar to the crucial signalling function of monetary price in the real economy. This price function of toxicity, to the extent where there is transparency about the real amounts of toxicity, can have two important and helpful consequences: acting as a brake on the increasing monetary price of new drugs, via a damping effect on demand; and assisting individual patients in the informed contemplation of chemotherapy decisions. However, there are two problems that currently impede the effective dissemination of this highly desirable toxicity information. First, a prediction of toxicity in individual patients is difficult. Second, the vast database of real toxic effects in community practice is rarely made available for public scrutiny. Both of these problems, which together constitute a form of hidden cost, are potentially resolvable at least to some extent. In the absence of accurate information on toxic effects, it is easy for monetary price to progressively diverge from true value. We believe that improved transparency with respect to toxic effects, and better toxicity prediction, offer a better and more genuinely market-orientated solution to the issue of price distortions than the bureaucratic imposition of price controls.