In the colour reactions for strychnine identification several oxidizing reagents are employed. These tests give the same succession of colours, violet-blue, purple, and then red. On standing it changes to orange. This result points out a same course of reaction and that the colours come from the tested substance, not from the employed reagents, as has been proposed recently for some tests. We looked for Organic Chemistry information about strychnine oxidation. Apart from the structure of the complex oxidation product, there is no sequence or reaction mechanism advanced. So, we provided the electron, flow, step by step, from strychnine to the oxidation product described. We employed chromic acid and reached the same final product obtained when potassium permanganate was used. This result confirmed that a unique reaction course takes place during these oxidations.