The last few weeks if i eat a salad i have diarrhea 20-30 min after eating and there is already un digested veggies in my stool. this can't be normal.

This is something: That should be explored with a doctor in the office. Have you been losing weight? Are you having any other symptoms? What about other foods? What do you put on/in your salad? Have you tried eating the individual components of salad e.g. lettuce alone, carrots alone, dressing alone, and observed your reaction? Have you ever had issues like this in the past? Try a food diary and see your MD.