Social media is increasingly used to obtain health information and may influence decisions regarding medicines and herbal remedies. This study assessed the knowledge, attitudes, and practices (KAP) related to the impact of social media on medicine and herbal remedy use among the general public in southern Libya. A cross-sectional study was conducted among 215 participants using a structured questionnaire assessing socio-demographic characteristics, social media use, and KAP regarding health information obtained through social media. Descriptive statistics and chi-square tests were used for data analysis. The mean age of participants was 21.87 ± 6.67 years, with females (90.7%) and students (91.6%) predominating. Almost all participants (99.1%) used social media, and 89.8% followed health-related pages. Good knowledge was observed in 47.9% of participants, while 35.3% had moderate and 16.7% had poor knowledge. Overall attitudes were generally positive, with 74.4% showing a positive attitude. However, inappropriate practices were common: 44.2% had started a medicine or herbal remedy based on social media information, 20.0% had changed medication doses, and 27.9% had stopped prescribed medication. 15.3% reported these actions to a healthcare professional. Overall, practice scores indicated poor practice among all participants. Although participants demonstrated generally good knowledge and positive attitudes toward health information on social media, inappropriate medication-related practices were common. Public health education and greater involvement of healthcare professionals are needed to promote the safe and responsible use of online health information.