This study looks at how certain types of probiotics, called *Lactobacillus reuteri* (specifically strains ATCC PTA 5289 and DSM 17938), might help kids who have viral upper respiratory tract infections. These infections can cause symptoms like coughing, fever, sneezing, or a runny nose. The study aims to see if these probiotics can reduce the number of sick days and pain children feel.

To join, kids need to be between 4 and 17 years old, have symptoms of an upper respiratory infection, and test negative for strep throat. They should not have taken antibiotics or other probiotics recently, and should not have certain medical conditions. A parent or guardian needs to agree to the study, and kids over 6 can also give their consent.

Key Points:

• The study is for children aged 4-17 with certain cold symptoms.
• Participants must not have used antibiotics or other probiotics recently.
• Parental consent is required for participation.