Unlike those following Clark's method, a number of flushers don't do parasite cleanses and even author Andreas Moritz is resolutely against the practice. Here are some posts by him that explain his stand on the issue:

"As I have mentioned several times before on this forum, I generally don't endorse parasite cleansing as such. What you try to kill only grows stronger. You can kill some parasites but not all, especially if the liver isn't clean. New parasites or their eggs enter the body all the time. They only proliferate in an filthy environment that is cut off from oxygen. Waste deposits are their primary target and they help to decompose it. It is not an ideal situation, but better than having the waste just sit there."

"In a clean body, parasites can do no harm. On the other hand, you can do a great parasite cleanse getting out a lot of critters and worms and a week or two later be infested again. So parasites are not the problem here, just as bacteria are not really responsible for an infection. Some liver cleanse procedures don't include the proper preparation (i.e. softening of stones, colon cleanse, low protein diet, etc.), which can make it difficult to get out stones. However, if done properly, you don't need to kill off parasites to release hundreds or sometimes even thousands of stones at a time."
"As you might have heard I am not a great friend of killings things in the body, including parasites, fungi, bacteria. To do so would leave billions of corpses of organisms behind that often cause more problems than if they were kept alive (to do their job of decomposing waste products and weak or dead cells). In fact, some of the debris may enter the lymph and blood and overtax the liver, kidneys and skin. Cleansing the liver bile ducts and the colon, and adjusting to a more balanced diet and lifestyle, would be a more efficient way to deal with parasitic presence, leaky gut, and skin problems."

"Once the liver and colon are clean and the diet/lifestyle are balanced according to your body's type and needs, parasites cause no harm in the body, just as Candida bacteria in the large intestine pose no problems if kept in check by the friendly probiotic bacteria. Both are needed in the body and there is no conflict between the two.

"This makes the need for parasite cleansing prior to Liver Flushing obsolete. Thousands of people have done it this way with great success and had no problems.

"As explained before, parasite cleansing is an attempt that often fails, similar to Antibiotics to kill germs. The germs come back, a little stronger each time.

"Parasites tend to grow in in an acidic environment generated by presence of undigested foods or waste that has not been removed. You cannot completely live without parasites, and they are harmless when the body is clean inside and food diet is supportive of the digestive functions. Killing them poses a problem in that it leaves millions of dead corpses of parasites around that, in turn, require decomposing bacteria to destroy them. Meat (carcasses)harbors a lot of parasitic worms and eggs that survive the acid assault (HCL) in the stomach. Eating a balanced vegetarian diet that suits one's body type and following the proper meal times to optimize digestion goes a long way in removing the need to employ parasites to do the job that the body can no longer do.
"Normally, bile secreted by the liver keeps the parasite population in check. A few liver cleanses, though, rarely open the bile ducts enough (or keep it them open long enough) to restore intestinal pH to normal levels and thus prevent parasitic infestation. Bile flow must be completely unhindered to do that. Apart from continued Liver Cleanses make sure to avoid congesting foods that also trigger mucus reactions and cause coating of tongue (see Timeless Secrets of Health & Rejuvenation, http://www.ener-chi.com,
for more details).
"With regard to your question on parasite cleanses, I won't be able to give you a satisfying answer. I used to prescribe them about 10 years ago but got disappointed for lack of major, long-lasting benefits. On the other hand, I had excellent results when people used the liver cleanse, combined with colonics and adjustment of their diets. I found that those who ate meat and continued to eat meat or other kinds of dead flesh foods, including fish, had the most parasites and worms. It is very natural for these things to spread in putrefying, coagulated (through heating or cooking) protein. In these cases, using the parasite cleanses turned out to be useless and a waste of money and effort. Those who ingested mostly cooked and vegetable produce, salads, fruit, grains and pulses had the least or no parasitic infestation. In other words, doing a parasite cleanse may have no true benefits unless your digestive system is cleaned out and your diet does not support parasite growth; but if you do those things, a parasite cleanse may not even be necessary anymore. "

"As long as there are stones in the liver bile ducts, parasites can repopulate in a matter of days. Parasites can only be found where waste matter is present. As long as digestion is poor, parasites have fertile ground to thrive and spread. You cannot kill them all or all of their eggs and even if you did, they can be back in no time through food or other ways. But once the liver is clean and diet and lifestyle are balanced, parasite problems would be a non-issue."
"To develop an HCV infection, you have to have at least several thousands of such stones congest the bile ducts of the liver. I don't agree that HCV is incurable. The hepatitis C virus attacks liver cells that are weak, damaged, wornout, that have lost their ability to produce Interferon. The stones in the bile ducts knick of blood vessels, nerves and lymphducts, thereby weakening liver cells and making them prone to infection. The virus is not there to destroy the liver. Quite to the contrary. It destroys as many of these damaged or weak cells as possible to prevent them from turning cancerous. By removing the stones, you are setting the precondition for self-healing to occur. "
"Clark's protocol does not include the preparatory period for softening the stones, as well as colon cleansing both before and after the liver flush. Especially the latter steps are very important in order to avoid a toxicity crisis which could result from stones becoming trapped in the colon during the cleanse. "
"The virus in the brain didn't come from the outside, it was made inside. Viruses don't cause diseases. They manifest themselves from fungi material when the cell interior's pH is very acidic. Fungi develop from bacteria in an acidic cell terrain. Bacteria develop from cell particles in a slightly acidic cell milieu. When the cell's pH is alkaline, no micro-organisms are able to develop. Likewise, external germs enter only terrains that are acidic, and as such, are supportive of their activities. Viruses go by vibration. They don't have a nose or ears, yet they always go to places where there is work for them to do. They help prevent cell mutations and other serious illnesses. They are wrongly blamed. If you see the virus as your enemy, it will become your enemy. You bestow power to everything you perceive
Physically, cleansing the liver, kidneys and colon, and eating mostly alkaline-forming foods (see also Timeless Secrets of Health and Rejuvenation) restore a pH terrain that no longer creates or attracts germs.
"It is an unproven myth that viruses (or bacteria) cause disease. Even Luis Pasteur had to admit at the end of his life that he made a mistake in announcing that bacteria cause infection. A certain milieu attracts the right kind of bugs to decompose or destruct what is no longer in the body's best interest. And so, just because virus material is found in infected cells doesn't mean viruses are responsible for the infection. Most of us have most viruses and bacteria that exist outside the body, right now inside the body. There are no real boundaries between the inside and outside. Whatever exists outside also exists inside. Killing germs may bring relief, but more often than not this causes a recurrence or has a "deepening" effect. When suppressed through treatments of symptoms versus causes, toxins and waste products penetrate areas of denser tissue in the body, like bones, spinal columns and joints, weakening the body further. This requires new "diseases" (survival mechanisms) to help prevent even worse calamities. They are not diseases either, just ways to cope and prevent death from occurring."

"Killing the virus in the mouth means very little. All you do is prevent the virus from doing its precious job. Viruses can go anywhere in the body, and wait, wait for the right occasion to help. Viruses don't act mechanically or randomly. They are blind by nature, but they naturally gravitate to places that resonate with them, that is, have the same vibrational frequency. Molecules, atoms, subatomic particles all receive and radiate energy at specific frequencies. Like attracts like. So when a part of your body vibrates on a lower frequency (for example, when congested with stones in the liver, protein in the blood vessel walls, or waste matter in the colon) you will automatically resonate with things that are of the same vibration. This can range from wanting certain low-frequency foods (junk foods, for example, attracting people towards you that are negative, doing things that make you feel sad, fearful or depressed, to attracting germs to your body that help you infect and remove what is of that same lower frequency. There are no accidents when it comes to viral infection. Viruses simply cannot go to areas of higher vibration. Thus a healthy, clean cell cannot be infected by any kind of virus. There is simply too much protection and too little attraction for that to happen."