The only "natural" remedy is waiting, and letting the body do its job.
When you are ill, simply let the body do its job.
Does your body signal thirst? Then drink water.
Does your body signal hunger? Then eat something. A nice fatty chicken soup, free of seed oil, for example, is usually considered good food when you are ill.
And if your body signals pain, then it signals that something is not good. Can you stop it? Then stop it. If your leg hurts (say because it is broken), then pain signals you to not use the leg.
Does your body send other signals you can easily understand? Follow them.
In most cases the body signals what it needs. Simple, isn't it?
What, that is not enough for you? You want to do more? You think there must be better ways? You know you can better than that? Fine, there is – depending on your disease – some more help. But none of it a "natural" remedy – so please, stop using that word. After all, you wouldn't try some "natural" strychnine, even if it were 100 % pure organic, now would you?