Many modern medicines are derived from plants, but only providing the active ingredient. Herbalists will argue that other co-factors in the plant work in conjunction with the active ingredient to make it more efficacious - and they are probably right in most cases, a primary motivation for supplying refined ingredients is to be able to patent and brand a normally generic substance.
A couple common herbs for inflammation, and their modern counterparts:
Of course, a proper paleo diet will reduce systemic inflammation. Inflammation is a constant battle in the human body though, so eating a diet rich in ginger, turmeric and other plant-based anti-inflammatories isn't a bad idea.
It is almost always worthwhile to attempt to reduce inflammation from acute injuries. While some inflammation opens up blood vessels and brings more nutrients to the area of injury, too much inflammation can restrict flow and have the opposite effect. The body is greatly tuned to over-exaggerate the inflammation response in acute injuries. This is because inflammation not only starts the healing process, but it immobilizes the injury. Think of a sprained ankle or broken bone: the goal of the excessive amounts of inflammation in these injuries can cause is immobilization, allowing the animal partial usage of a damaged limb. Healing is almost always faster when the inflammation response can be toned down a little. Corticosteroids, which are definitely not paleo, likely go way too far in reducing the inflammation response beyond what is necessary for proper healing, but herbal anti-inflammatories aren't going to have nearly that great of an effect.
Another way of reducing acute inflammation is an ice bath, or contrast hydrotherapy (alternating cold/hot water every minute or two).
Another herbal concoction that I like to take after an acute injury is "Dr Christopher's Bone Flesh and Cartilage" (BFC). This is just a recipe for a set of herbs that are useful in stimulating the healing process and providing nutrients needed for healing, any quality herbalist will carry this recipe.