Biotrexate 1000mg Injection is a medicine used for treatment of cancer in various parts of the body such as breasts, head, neck, lungs, blood, bone, lymph, and uterus. It may be used with other medicines as part of combination therapy. Biotrexate 1000mg Injection is given under the supervision of a healthcare professional and should not be self-administered. Your doctor will decide what dose is necessary and how often you need to take it. This will depend on what you are being treated for and may change from time to time. You should take it exactly as your doctor has advised. Taking it in the wrong way or taking too much can cause very serious side effects. It may take several weeks or months for you to see or feel the benefits but do not stop taking it unless your doctor tells you to. You should avoid drinking alcohol as it may increase your risk of liver damage. The most common side effects of this medicine include nausea, vomiting, loss of appetite, abdominal pain, tiredness, and mouth sores. Your doctor may advise you to take folic acid to reduce some of these. If they do not go away or get worse, tell your doctor. There may be ways of preventing or reducing these effects. It is a very strong medicine and some people may develop serious side effects while taking it. This medicine may lower your ability to fight infections and lead to problems with your blood, liver or kidneys. Your doctor will advise you regular blood tests to check for these. Before taking it, tell your doctor if have stomach, liver, or kidney problems or are taking any medicines to treat infections. Many other medicines can affect, or be affected by, this medicine so let your healthcare team know all medications you are using. This medicine is not recommended during pregnancy or while breastfeeding. It may harm your baby. You and your partner should avoid becoming pregnant or fathering a child for several months after your treatment with it has stopped. Your doctor may perform several tests such as blood tests, X-rays and physical examinations both before and during treatment with this medicine.