Natural Justice is a charity that conducts research on the causes of criminal behaviour, and especially on the related effects of nutrition. Natural Justice carried out an experiment in the Aylesbury Prison for young offenders. In this study, published in 2002, inmates were randomly assigned to receive either a dietary supplement or a placebo. Neither the inmates nor the guards knew who received what. Those receiving the supplements, which contained vitamins, minerals, and fatty acids, committed 37 ewer serious or violent offences in prison. The difference disappeared when the nutritional supplementation was halted.

In English law, natural justice is technical terminology for the rule against bias (nemo iudex in causa sua) and the right to a fair hearing (audi alteram partem). While the term natural justice is often retained as a general concept, it has largely been replaced and extended by the general "duty to act fairly".