Pepper heat is measured in Scoville units.
Bell pepper: <50
Jalapeno: ~ 2,000 to 5,000
Cayenne: 30,000 to 50,000
Habanero: 100,000 to 350,000
Dave's Insanity Sauce: 500,000 to 700,000
Bhut Jolokia (Ghost Pepper): 850,000 to 1,000,000
Da Bomb Sauce: 1,500,000
Pure capsaicin: 16,000,000
Dosing someone with 1.5M Scoville pepper sauce is not a joke and in some cases could cause damage the mucosa lining the gut of someone not a regular pepper eater (you do adapt, but it takes time.) Even if it doesn't, the extreme discomfort would, in most jurisdictions, be considered an assault if administered covertly.