There are no authoritative statistics comparing the side effects of Cialis, which is the trade name of Tadalafil tablets, and Viagra, which is the trade name of Sildenafil citrate tablets, and it is not possible to say which one has fewer side effects. Tadalafil tablets and sildenafil citrate tablets belong to the same class of phosphodiesterase type 5 inhibitors, and are suitable for the treatment of erectile dysfunction in men over 18 years of age. However, there is no authoritative study on the comparison of the side effects of these two drugs, and the presence or absence of side effects and their severity may vary depending on the physical condition of the user, drug compliance and other differences in individual differences. Therefore, it is not possible to give an accurate answer to the question of which side effect is less, tadalafil tablets or sildenafil citrate tablets. In addition, it should be noted that tadalafil tablets and sildenafil citrate tablets are prohibited for people who are allergic to them, and it is also prohibited to combine with nitrate drugs (such as nitroglycerin), guanylate cyclase agonists (such as levocetirizine) and other drugs, and there may be headache, hot flashes, and other adverse reactions in the process of using the drug. In summary, the diagnosis of erectile dysfunction, must be under the guidance of the doctor according to the actual situation of the individual choice of medication, do not blindly take drugs or increase or decrease the amount of drugs, so as not to cause adverse consequences.