The corrosion inhibition properties of Piper longum fruit extract and Bacopa monnieri stem extract in 1 M sodium hydroxide (NaOH) solution was studied using chemical technique. Both extracts inhibited the corrosion of aluminium in NaOH solution. The inhibition efficiency increased with increasing concentration of the extracts. The Piper longum fruit extract was found to be more effective. The Piper longum extract gave 95% inhibition efficiency.