Acorus calamus is an aperture-opening drug, and its side effects are not yet known, so it is important to follow doctor’s instructions when using the drug. Acorus calamus is pungent, bitter and warm in nature, and belongs to the heart and stomach meridians. It can open the orifices and dispel phlegm, awaken the mind and promote wisdom, dissolve dampness and open the stomach (by removing dampness, the gastrointestinal function is normalized), and dispel wind and dampness (by removing wind and dampness in the body). The main treatment of phlegm and dampness obscuring the clear orifices (obscuring the seven orifices of the mouth, eyes, nose and ears) caused by delirium; damp obstruction of the middle Jiao (dampness impedes the function of the spleen and stomach) caused by abdominal distension and pain; forgetfulness and insomnia, tinnitus and deafness; pain in the joints and unfavorable bending and stretching; bruises and other injuries. Calamus can be combined with Xiangshu, to treat abdominal distension and pain caused by cold condensation and stagnation of qi; with Yu Jin, to treat confusion caused by fever; with Hou Pu, to treat abdominal distension and fullness caused by dampness and obstruction of the abdomen, and lack of appetite; with Peilan, to treat nausea and vomiting caused by dampness obstruction of the middle Jiao, and liver and stomach disharmony (disharmony of the liver’s ascending and stomach’s descending functions), stuffiness and swelling of the chest and abdomen, diarrhea, and so on. Calamus should be used with caution in cases of yin deficiency, irritability, excessive sweating and vomiting of blood. Adverse effects are not known. Please consult a healthcare professional for advice. Patients who are not feeling well are advised to consult a doctor in time to avoid delay.