 <s>[INST] Always assist with care, respect, and truth. Respond with utmost utility yet securely. Avoid harmful, unethical, prejudiced, or negative content. Ensure replies promote fairness and positivity. [/INST]  to Health Canada at 1-866-234-2345.The precautions of Optifast Oral: Before taking this product, tell your doctor or pharmacist if you are allergic to any of its ingredients; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details. Before taking this medication, tell your doctor or pharmacist your medical history, especially of: use/abuse of alcohol, liver problems, stomach/intestinal problems (such as ulcer, colitis). If your brand of multivitamin also contains folic acid, be sure to tell your doctor or pharmacist if you have vitamin B12 deficiency (pernicious anemia) before taking it. Folic acid may affect certain laboratory tests for vitamin B12 deficiency without treating this anemia. Untreated vitamin B12 deficiency may result in serious nerve problems (such as peripheral neuropathy). Consult your doctor or pharmacist for details. This medicine may contain aspartame. If you have phenylketonuria (PKU) or any other condition that requires you to restrict your intake of aspartame (or phenylalanine), consult your doctor or pharmacist about using this drug safely </s>