Diberal, also known as 5-(1,3-Dimethylbutyl)-5-ethylbarbituric acid or DMBB, is an atypical barbiturate.

Diberal, unlike most barbiturates, can have convulsant actions.

This is uncommon, as barbiturates typically enhance the function of GABA as allorestic modulators and agonists (at higher doses),[2] therefore having anticonvulsant properties.

It is atypical in the means that it has convulsant action, unlike most barbiturate drugs.

It has been found that administration of (−)-DMBB reverses the convulsant actions of (+)-DMBB.