Hello and Welcome to ‘Ask A Doctor’ service. I have reviewed your query and here is my advice. Krimson 35 Tablet is an oral contraception used for preventing pregnancy, hormonal replacement therapy, prostate cancer and postmenopausal osteoporosis. It has Ethinyl Estradiol, Cyproterone which helps in maintaining the normal estrogen level in the body. Nausea and vomiting is the most common side effect of Krimson 35 and of all the other birth control pills. There is no specific treatment for nausea caused by the pill. However, you may find relief from mild bouts of nausea with these home remedies: -Consume only light, plain foods, such as bread and crackers. -Avoid any foods that have strong flavors, are very sweet, or are greasy or fried. -Drink cold liquids. -Avoid any activity after eating. -Drink a cup of ginger tea. -Eat smaller, more frequent meals. About your hypothyroidism, I want to say that Eltroxin or Levothyroxine doesn t directly interact with birth control pills, but estrogen containing in most of birth control pills, can affect thyroid levels which could possibly necessitate an alteration on your levothyroxine dose. For this reason, i suggest to consult your treating doctor because you may need to adjust the dosage of your Eltroxin in order to have normal TSH result while you re on contraceptive pills. Hope I have answered your query. Let me know if I can assist you further.