Cough Medicine

I have been sick for the past week, I think it was the flu. I had a flu shot in the Fall but that only protects against previous versions of the flu. The weather in Taiwan has been unseasonably cold, so lots of people have coughs, fevers, ... The most annoying part has been the cough, I tried almost every "over the counter" medicine but none of them seemed to have an effect. Here's by current collection:

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None of them seemed to control the cough, so I went to a pharmacist and asked for his recommendation. He quickly pointed me to this medicine which I think comes from Japan.

Why did this one worked when all the others were ineffective in stopping the cough? The magic ingredient is right of the box:

Codiene can stop the cough, being a component of opium is why it is not available in the US. I remember in the 1970s, kids in Minnesota would drive to some backwater drugstore in South Dakota and clean out the shelves of cough medicine with codiene. Of course, it wasn't to cure a cough but to get high. I think sometime in the 70s the US stopped using codiene in "over the counter" medicine. I know in Canada some codiene products are still available. And in Japan it seems OK too. I recommend codiene, but only for medicinal uses.