Sorry, not used holistic alternatives for either of these, but am looking forward to seeing the replies for Frontline alternative (quite happy with Drontal).
http://www.denes.co.uk/advice/fact_sheets/fleas.phpDenes produce 'alternatives' and they've got a fact sheet (click on link above) for suggested flea treatment, and if you look in the drop down menu at the top of the page, there's also one for ticks and parasites. I think the recommendation is use of garlic.