Objective To identify symptoms of COVID-19 in adults in the scientific literature. Method Systematic review of studies published from December 1, 2019 to April 21, 2020 from the Scopus, Web of Science and PubMed databases, in order to answer the following research question: “What are the symptoms caused by COVID-19 in adults?” using the keywords “Symptoms”, “Clinical Manifestations”, “Coronavirus”, “COVID-19”. Results Of the total 105 references, 13 references that addressed the symptoms of COVID-19 were selected. Fever and normal or dry cough were symptoms present in all studies. Conclusion The symptoms identified in adult patients were fever, normal or dry cough, headache, pharyngalgia, dyspnea, diarrhea, myalgia, vomiting, sputum or expectoration, anxiety or chest pain, fatigue, nausea, anorexia, abdominal pain, rhinorrhea, runny nose or nasal congestion, dizziness, chills, systemic pain, mental confusion, hemoptysis, asthma, taste disorder, smell disorder, belching and tachycardia.