Photodynamic therapy (PDT) uses a non-toxic photosensitizer (PS) and visible light to generate cytotoxic species, offering dual selectivity for targeting pathogens and lesions. While PDT has been used in vitro to kill bacteria, its application in treating infections in animal models and humans is still developing. Gram-negative bacteria are generally resistant to PDT, but certain PS with cationic charges or agents that increase outer membrane permeability can enhance its efficacy. Multi-antibiotic-resistant bacteria are as susceptible to PDT as non-resistant strains, and resistance to PDT is unlikely. PDT is effective for localized infections, requiring PS selectivity for microbes, delivery to the infected area, and effective illumination. Recent studies show PDT's use in treating viral lesions, acne, Helicobacter pylori infections, and brain abscesses. Possible future applications include treating infections in wounds, burns, and abscesses. PDT's advantages include dual selectivity, minimal systemic toxicity, and potential for targeting biofilms. It has shown promise in treating infections like H. pylori, acne, and oral candidiasis. Clinical trials suggest PDT's efficacy in treating localized infections, with potential for broader applications in immunosuppressed patients. PDT may also inactivate virulence factors, making it a potential "anti-virulence factor therapy." While still in early stages, PDT offers a promising alternative to antibiotics for treating infections, particularly in cases of antibiotic resistance and biofilm infections.Photodynamic therapy (PDT) uses a non-toxic photosensitizer (PS) and visible light to generate cytotoxic species, offering dual selectivity for targeting pathogens and lesions. While PDT has been used in vitro to kill bacteria, its application in treating infections in animal models and humans is still developing. Gram-negative bacteria are generally resistant to PDT, but certain PS with cationic charges or agents that increase outer membrane permeability can enhance its efficacy. Multi-antibiotic-resistant bacteria are as susceptible to PDT as non-resistant strains, and resistance to PDT is unlikely. PDT is effective for localized infections, requiring PS selectivity for microbes, delivery to the infected area, and effective illumination. Recent studies show PDT's use in treating viral lesions, acne, Helicobacter pylori infections, and brain abscesses. Possible future applications include treating infections in wounds, burns, and abscesses. PDT's advantages include dual selectivity, minimal systemic toxicity, and potential for targeting biofilms. It has shown promise in treating infections like H. pylori, acne, and oral candidiasis. Clinical trials suggest PDT's efficacy in treating localized infections, with potential for broader applications in immunosuppressed patients. PDT may also inactivate virulence factors, making it a potential "anti-virulence factor therapy." While still in early stages, PDT offers a promising alternative to antibiotics for treating infections, particularly in cases of antibiotic resistance and biofilm infections.