What should be done for an overdose of diet pills?

It Depends on pill: There are several types of wt loss pills and the adverse effects are different. For example: xenical/ali is a fat blocker and and od probably won't cause much problem if you don't eat very fatty foods. Phentermine od can be serious: cardiac arrhythmias/heart attacks etc..Belviq--a new one and i don't know the answer. Consult doc asap if u or someone u know od'd. Good luck.