This chapter from Outdoor Emergency Care: A Patroller’s Guide to Medical Care provides a detailed overview of altered mental status, a critical concept for outdoor emergency care technicians. It defines the condition, explores its numerous potential causes using the mnemonic AEIOU-TIPS, and outlines the assessment and management of patients experiencing it. The text further discusses specific conditions that can lead to altered mental status, such as seizures, hypoglycemia, hyperglycemia, and stroke, including their signs, symptoms, and initial care. Ultimately, this resource equips OEC technicians with essential knowledge for recognizing and responding to patients with changes in their level of awareness.