h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

I am a defence member and have been exposed to both CS and OC spray in the course of my training.

CS: Designed to effect the respiratory system and incapacitate an aggressor. I makes every pore you have run, eyes, nose, throat, ears and the rest all runand it is hard and painful to draw breath. You are in generally a bad way and not able to resist much at all.

OC: standing for oleoresin capsicum. This is the sap of certain peppers, scotch bonnet is a favourite, distilled to about 2 million Schoville Heat Units (SHU). Tabasco sauce is around 60 000 SHU. OC spray on your face will make CS seem like a delicate facial. You will drop to the ground, kick, scream and generally wish your mummy was there to make it all better. All you can do is wash it away as best as possible and try to get over it. There have been cases of people fighting through OC but they have mostly been on hard drugs and felt it in the end.

OC is bad stuff and will hurt you. The only defence is a really good Mil Spec gas mask and about 100 meters.