"What are the best probiotics to take while taking antibiotics (Keflex) and how far apart should they be spaced?"
Taking antibiotics with any sort of beneficial bacteria is foolishness, because antibiotics kill the helpful bacteria. It is pointless to attempt a rebuilding of the intestinal flora until antibiotic usage has been completely ceased, due to the aforementioned reason. We figure that you are trying to minimize the impact of the antibiotics upon your long-term health, but there will always be consequences to antibiotic usage, and there is no way to escape with probiotics or anything else. The effects of taking antibiotics cannot be simply neutralized by probiotics. It is wisest to avoid antibiotics in general, except in the most extreme of cases. Extreme cases are the do-or-die ones, like brain infections (meningitis), wherein we would recommend immediately attacking the invader with anything and everything.
Natural antibiotics from alternative medicine likewise kill the beneficial bacteria, but they do not cause the long-term toxicity problems of the pharmaceuticals, which make it difficult for beneficial colonies of bacteria to revive.
Yogurt is the truest and most natural probiotic. It is the real deal. It has a fantastic history of being completely safe and effective. The people making yogurt do not need to wear hazardous material suits, they are not biotechnology engineers, and yogurt is not likely to originate from child slaves in a Chinese chemical cesspit.
We have not done enough research of probiotics to know if any of the available probiotic 'supplements' truly have an acceptable help-to-harm ratio. We are confident that we would be aghast at the manufacturing processes from what we already know. The idea of 'supplementing' with probiotics is very new. A generation ago, people only supplemented with whatever vitamins and minerals that they lacked, which was wise. People have historically (and rightfully) believed that intentionally consuming raw bacteria was an insane abomination against nature, but it has somehow become trendy and hyped now. Throughout most of history, people did not need such 'supplements', and they should not need them now. Our forefathers did not need probiotics, because they did not routinely poison themselves so thoroughly that critical intestinal bacteria died.
The big picture that many of our readers have missed is that the chemical industry is never going to save us from ourselves. The probiotics hype is another financially-lucrative trick to get us to pay them for the privilege of committing germ warfare against ourselves. It is really incredible when one pauses to contemplate it all, and they are meanwhile making fools out of so many of our people. They actually used the principle of flora stimulation from legitimate alternative medicine, and then they spun it to mean that we need to swallow pills of germs, and even pay them for it. Most incredible is the fact that the new scam is intended to fix the health damage that was caused by their other 'solutions', and yet so few ever learn the pattern.