There are some patients who feel pain at the beginning of taking such drugs as glucosamine. There are several reasons for this situation: 1. Glucosamine is a class of slow-acting drugs, so the therapeutic effect is not reflected in the initial stage. Because the degeneration of the cartilage in the joint and the inflammation inside the joint are serious in the early stage. At this time, the effect of the drug is not reflected, the patient will feel the symptoms are more obvious, there is pain. 2, may be due to the patient did not protect the joints in a timely manner. Some patients think that they can effectively relieve osteoarthritis by taking such drugs, so they do not pay attention to the protection of the joints after taking the drugs. In the initial stage, the effect of the drug is not reflected, and the patient does too strenuous activities, which can lead to increased damage to the joint, and then produce pain. 3, may be due to the anti-inflammatory effect of these drugs is too weak. Although these drugs have some effect on eliminating inflammation, they are not strong enough. If the patient has heavy inflammation inside the joint in the early stages, such drugs alone are not enough. In summary, the above types of reasons cause some patients to have more pain or more pronounced symptoms in the early stages of taking this medication.