Viagra (sildenafil) and Cialis (tadalafil) are world-famous medicines which are considered the most effective remedies for achieving good erection and enhancing sexual life. A great number of men throughout the world take these drugs separately in order to fight erectile dysfunction. Some men are eager to know whether it is possible to take both drugs to achieve more substantial effect. **30ml dropper bottle, liquid suspension ** FOR RESEARCH PURPOSES ONLY  The chemicals/materials for sale here are intended for laboratory and research use only, unless otherwise explicitly stated. They are not intended for human ingestion or for use in products that may be ingested.