The difference between metformin hydrochloride extended-release tablets and enteric-coated tablets is that they are made differently. Extended-release tablets can be released slowly in the stomach and are taken once a day; enteric-coated tablets do not dissolve in the stomach but enteric-coated tablets are released in the intestine and require multiple doses per day. Metformin hydrochloride extended-release tablets incorporate a slow-dissolving material to encapsulate the medication so that metformin can be released slowly in the stomach and continue to work, prolonging the duration of the medication’s action while also reducing the irritation of the medication in the gastrointestinal tract. It can be taken once a day at a higher cost. Metformin enteric-coated tablets are made with a layer of enteric coating wrapped around the outside of the drug, when the drug passes through the stomach, the enteric coating will not be destroyed in the acidic environment of the stomach, and when it enters the weakly alkaline environment of the intestine it begins to disintegrate and release the medicinal properties, which is able to avoid the irritation of the drug to the stomach. The medication needs to be taken several times a day, the whole tablet before meals, the price is relatively cheap. The two have different production processes, but the indications, adverse reactions and contraindications are the same, and they are mainly used for the treatment of type II diabetes mellitus. Adverse reactions include nausea, vomiting, diarrhea, dizziness, and hypotension. Contraindications include hypersensitivity to the product and its components, type II diabetes mellitus with ketoacidosis, hepatic and renal insufficiency, heart failure and so on. It is contraindicated in pregnant and lactating women. Metformin belongs to the prescription class of drugs, need to be used under the guidance of a doctor, how to choose can be weighed against the price, effectiveness, and patient compliance and so on.