system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5. Why is honey and lemon a popular cure for cold like symptoms. What makes lemon more effective than say an orange or lime?
gpt
Any lighty acidic hot beverage with fructose (or sucrose) would cause the same effect of reducing coughing (most regular cough "medicine" is 99% sugar), so if you ran out of lemon you could try with apple cider vinegar, and honey can be really substituted with any other syrup.

Lime would be ok but most orange variants are heavily engineered towards sweetness in detriment of acidity, so not as effective.

A century ago, the original treatment on Europe was hot herbs/lemon liquors (diluted in water) and sweet wines, which also comes with a few extra "side effects".