I've read that adults can take up to 1000 IU of vitamin D3 per day. You can also get your blood checked for vitamin D levels, and then see how much extra vitamin D you actually need.
Female, Age 20
9 Asacol, Rowasa, 1000 mg Canasa, Proctofoam, Rifaximin 2/day
Digestive Advantage (Crohn's & Colitis), 1 Florastor, 50 mg 6MP, 1 Primadophilus reuteri, Remicade (7 infusions), 2.4 g Lialda, Forvia, 6 Colazal, 1 Anucort, Culturelle, Fish Oil, Calcium/Vit D supplement, 20 mg Prozac, VSL #3 DS, Turmeric