Valid consent to medical treatment.

When consent to medical treatment is described as 'valid', it might simply mean that it has a sound basis, or it could mean that it is legally valid. Where the two meanings are regularly interchanged, however, it can lead to aspects of the sound basis or the legal requirements being neglected. This article looks at how the term is used in a range of guidance on consent to treatment and argues for consistency. © Author(s) (or their employer(s)) 2020. No commercial re-use. See rights and permissions. Published by BMJ.