Yes, allergic reactions to Tadalista 20 (which contains the active ingredient Tadalafil) can occur, although they are rare. Possible allergic symptoms include rash, itching, swelling (especially of the face, tongue, or throat), severe dizziness, and trouble breathing. These signs indicate a serious allergic reaction and require immediate medical attention. Additionally, individuals allergic to Tadalafil or any of the inactive ingredients in Tadalista 20 mg should avoid using the medication. It's also important to consult a healthcare provider before starting Tadalista, especially if there is a history of allergies or sensitivity to similar medications such as Sildenafil (Viagra) or Vardenafil (Levitra).