In a 2 quart saucepan, melt butter or margarine over medium heat. Add onion, green pepper, celery, and garlic; cook until tender.
Mix in cornstarch. Stir in stewed tomatoes, tomato sauce, Worcestershire sauce, chili powder, and red pepper sauce. Bring to a boil, stirring frequently. Stir in shrimp, and cook for 5 minutes.