Well, if they're hysterical, just choke 'em out. Repeat until they chill. Okay, seriously.... 1) People tend to be wary of what they don't understand. Try educating them a bit. Invite them to watch training. The more they know, the less apprehension they'll have. 2) Point out that virtually any sport involving contact, even if it's not part of the sport, can lead to injury. I've known a guy who's got a limp for life resulting from a soccer injury,,,soccer not widely known for being a brutal bloodsport. But he connected with a ball full force the same time as someone else and folded his knee. You can get fucked up riding a bike, doing gymnastics, playing basketball. I once beaned my best friend in the head with a Titleist #3 coming off a shanked chip so goddam hard I thought I gave him a concussion...nothing serious, but one inch off in any direction and he could easily have been missing teeth, or sight in his left eye. You risk hurting yourself getting out of bed in the morning. 3) You might want to also point out that you've been training for some time will little ill effect. 4) Mention, as others have suggested, that you are training to be able to fight. Good training involves bleeding a little in the gym so you don't bleed a lot in the street.