As far as I know, there is no way to stop the bleeding with out constant pressure.
On the bright side, you only give up 1-3 CCs of blood due to leech bites.
The problem with leech bites and hiking is your heart is pumping harder while you hike, pushing more blood around.
Its not uncommon for the bite to last several hours.
However short of constant pressure or some type of sealant, I've not heard of anything you can do.
outdoors.stackexchange.com/users/76/Justin Self
I have heard that if you do not remove the leech until it gets full and naturally drops off that you will not bleed much, and that it is safer because you reduce the risk of infection.
At the moment I can't find good sources for this, only: How to Remove a Leech (Go Borneo Travel.
Com):
In case the leech has already got you, do not pull it out.
The commonly used techniques of burning, salting and squeezing result in the leech vomiting harmful bacteria back into your system.
Leeches fall out on their own once full.
If you can continue hiking with the thought of a small Dracula hanging off your body do so.
It will not take longer than 20 minutes for the leech to give up and remove itself safely.
How to remove a leech (Wild Madagascar.
Org):
NOTE:
Is it generally not advised to attempt removing a leech by burning with a cigarette; applying mosquito repellent, shampoo, or salt; or pulling at the leech.
This can result the leech regurgitating into the wound and causing infection much worse than the leech bite itself.
Not what I would consider reliable and no comment on bleeding specifically, so unless someone can corroborate this theory I shall eventually delete this answer.
outdoors.stackexchange.com/users/133/Mr.Wizard
Unlikely to help unless a tea bag is handy but the tannins in black tea bags contain tranexamic acid which helps clot blood.
Just had 5 hours of bleeding from a leech which didn't stop with heavy bandaging and elevation of my leg.
I applied a tea bag I had wet in tap water for 5 mins
and it hasn't bled since.
Old medical trick.
Its like an antidote to the chemical in the leech's saliva which actually stops you from clotting.
outdoors.stackexchange.com/users/8978/user8978
Septic pencil, bandage. Treatment: Leeches must be removed from the skin carefully.
If a leech is ripped from the skin, its fangs may break off and remain embedded, which induces ulcer formation.
Leech removal is facilitated by application of a few drops of alcohol, vinegar, or brine.
An alternative removal method involves the application of a lit match to the leech at the attachment site.
After leech removal, the site should be inspected carefully to insure that the fangs are absent.
Hemostasis (bleeding control) can be achieved by applying direct pressure and using a styptic pencil ( a short medicated stick, often made of alum that can be applied to a cut to stop bleeding), oxidized regenerated cellulose absorbable hemostat, or topical thrombin.
The wound should be cleansed thoroughly with an antiseptic several times daily and a multi-purpose topical antibiotic applied to prevent infection.
( source )
outdoors.stackexchange.com/users/3347/Mazura
I faced the same and a waiter at a restaurant suggested me this.
Just apply a pinch of turmeric at the spot a couple of times.
I worked wonders for me instantly.
Another report of this: http://gwens-nest.com/turmeric-a-spice-worth-knowing/ Cuts
/Bleeding: Turmeric has styptic properties.
This is a common kitchen remedy in India for minor cuts.
We have also stopped bleeding from minor cuts and wounds quickly by dusting them with turmeric powder.
I was SO happy to learn this tip, because the only other styptic herb I had heard of was cayenne, and I am a big scardy-cat about hot things in my mouth or on my bleeding wounds.
Turmeric doesn’t hurt or sting, but it leaves a yellow tinge to your skin.
outdoors.stackexchange.com/users/9780/Aditya
Plantago major (broadleaf plantain, white man's foot, or greater plantain) .
Image source Plantain is found all over the world, and is one of the most abundant and accessible medicinal herbs.
It contains many bioactive compounds, including allantoin, aucubin, ursolic acid, flavonoids, and asperuloside.
Scientific studies have shown that plantain extract has a wide range of biological effects, including wound healing activity, anti-inflammatory, analgesic, antioxidant, weak antibiotic, immuno modulating and antiulcerogenic activity.
So, tie some up on the wound with a gauze.
outdoors.stackexchange.com/users/13063/Jani Hyytiäinen
Put some paper ash (just burn a small piece of paper and collect the ash) in the area where you were bit.
Bleeding will stop.
outdoors.stackexchange.com/users/12808/Travel Enthusiast
Although leeches are relatively harmless, and you are not likely to bleed out from a bite, the blood stain on your clothes can be off-putting to your hiking buddies.  Is there any effective way to counteract the anti-coagulant leeches inject into the bite, and thus stop the blood-flow in a timely manner?
How do you stop blood-flow from a leech bite?
outdoors.stackexchange.com
<first-aid><leeches>
outdoors.stackexchange.com/questions/217
outdoors.stackexchange.com/users/86/Lost
Constant pressure is recommended to stop the bleeding, as well as application of septic pencil, paper ash or tea bag, and bandages. Alcohol, vinegar or brine help to remove the leech. However, it is said that waiting for the leech to naturally become full and drop off is a better way to reduce any risk of infection. Waiting for the leech to get full or using alcohol, a septic pencil and bandage can help with removal. You can also let the leech get full. Constant pressure, a black tea bag and paper ash can stop bleeding.
Constant pressure, a black tea bag and paper ash can stop bleeding. Leeches must be removed carefully with alcohol, a septic pencil and bandaged. Alternatively you can safely wait until the leech gets full.