Illumination devices for impinging light on tissue, for example within a body cavity of a patient, to induce various biological effects are disclosed. Biological effects may include at least one of inactivating and/or inhibiting growth of one or more pathogens, upregulating a local immune response, increasing endogenous stores of nitric oxide, releasing nitric oxide from endogenous stores, and inducing an anti-inflammatory effect. Wavelengths of light are selected based on intended biological effects for one or more of targeted tissue types and targeted pathogens. Light treatments may provide multiple pathogenic biological effects, either with light of a single wavelength or with light having multiple wavelengths. Devices for light treatments are disclosed that provide light doses for inducing biological effects on various targeted pathogens and tissues with increased efficacy and reduced cytotoxicity. Particular illumination devices are disclosed that provide safe and effective treatments for upper respiratory tract infections, including coronaviridae and orthomyxoviridae.