Spinal traction or decompression has the following proposed effects:

Facet Joint Mobilization
Various effects on facet joints are translation, sliding, separation, distraction, approximation, or compression of facet surfaces. Whereas there’s no empirical evidence, this movement leads to increased blood components and range of motion at the joints. Studies show that mobilization affects blood component levels and reduces inflammatory proteins.

Thus, it is recommended as a possible therapeutic method to lower inflammatory response, functioning as an anti-inflammatory mechanism. Spinal manipulative therapy relieves inflammatory cytokines but not substance P production in normal subjects.

Mechanical Spine Elongation
The consequence of spinal traction is decompression.