 This is a randomized controlled trial designed to evaluate the effect of dietary supplementation on endometriosis symptom remediation. Adolescent and young adults females aged 12 to 25 years with a surgically-confirmed diagnosis of endometriosis will be eligible for study participation. Subjects will be excluded if they have concurrent chronic illnesses that affect gastrointestinal absorption of nutrients e.g., celiac disease, IBD, cystic fibrosis, a history of renal stones, are pregnant, or non-English speaking. Once consented, subjects will be randomized to one of 3 treatment assignments: 1 vitamin D3 2000 IU daily n30, 2 fish oil 1000 mg daily n30, 3 placebo n30 and will take these daily for 6 months. Baseline nutrient intake from food and supplements will be assessed using the Food Frequency Questionnaire FFQ. The 142 item survey assesses usual dietary intake during the past year. Validated rating scales including the visual analog scale VAS, SF-36, and the World Endometriosis EPHect questionnaires will be used to measure pain and overall quality of life. The SF-36 measures 8 health concepts relevant across disease groups, including limitations to physical or social activities because of health problems, vitality, and general health perception. Patients will complete a full review of medication usage, past medical history, family history, and other lifestyle factors. Anthropometrics will be measured, and vital signs obtained. Measures will be repeated at 3-month intervals for a total of 6 months. Blood will be drawn at baseline, and at 6 months to measure levels of fatty acids, vitamin D, parathyroid hormone PTH, and calcium. 