Xpect LS Expectorant should be used with caution in children with hyperthyroidism (overactive thyroid) as it may worsen the condition. Inform the doctor if your child has hyperthyroidism before using Xpect LS Expectorant so that the dose may be adjusted appropriately. However, regular monitoring of thyroid hormone levels is recommended while using Xpect LS Expectorant for your child.