Originally Posted by Fat obi
According to this post / video, Magic Guard blocks Toxic Spikes entirely. However, another user claims that they remember their Clefable being poisoned in DP. It would be nice if someone could test this in HG / SS for verification in the most current game. Basically, lay down Toxic Spikes, switch a Magic Guard Pokemon into them.
I just tested right now. Two layers of Toxic Spikes were layed and I switched-in Magic Guard Clefable and it did not get poisoned. So, yes, Magic Guard blocks Toxic Spikes completely.