The present invention relates to the use of syringes for medicinal liquid injections into mammals, particularly humans, with the syringe bearing a marker ink to mark injection site with marker ink. The disclosed embodiments address re-injecting a medical liquid into the skin at the same location as previous injections. The practice of re-injecting medical liquids into the same location can result in indentions, hard lumps, or thickening of the skin, or lipohyperplasia. It can further cause medications such as insulin, to be inefficiently absorbed. Rotating injection sites within arms, thighs, stomach or buttock usually prevents or reduces this problem. A marker is used on the portion of the syringe that touches the skin of a recipient and causes ink or powder to be transferred to the skin of the recipient to mark an injection site for a desired length of time.
