Something I have noticed in my wanderings around the hills is the increasing amount of tissues, toilet paper and even worse, human excrement scattered far and wide. Often this mess is half heartedly covered with a loose rock or a few stones, paper and worse poking out from the edges. Apart from the fact it is unsightly, it is also unhygienic.
Now, I am sure the majority of backpackers are responsible folk and take appropriate measures. However, despite probably preaching to the converted, there are few items every person who walks in the countryside, and here I include those out just for a days walking. A small stuff sack or similar, in it a supply of toilet paper. It need not be a complete loo roll. Andrex sell 'On The Go' toilet tissue, sheets of tissue with no cardboard tube. They can be picked up in larger chemists. Also Coghlan's sell a similar item, obtainable from many outdoor shops. A small trowel, it does not need to be anything fancy or large. All that is required is that it is suitable for digging a small cat hole. A small bottle of hand gel for reasons of hygiene. Some backpackers also carry a lighter to burn toilet tissue. Have your toilet bag to hand as well. it is no good down the bottom of the rucksack.
Possibly stating the obvious, choose a place away from areas frequented by people, also, well away from water sources. Ladies, other items must be carried out. Always have a spare polythene bag to hand.
The golden rule is, leave no trace. Something I may add here. As someone who has had long term health problems for a fair while now, when wild camping, I now prepare and dig a cat hole well away from the tent when setting up camp. It is handier than stumbling around in the middle of the night in bad weather conditions, frantically trying to find somewhere to go by head torch. Just remember where you dug your scrape. If you do have to get up in the night, check in the morning that indeed everything is as it ought to be.
As I have said, the majority of backpackers abide by these unwritten codes of behaviour. However, we must all act responsibly.
We still have giardia and such like parasites, free water in the hills. In some countries even the remotest areas have polluted water.
As I say, just a few suggestions..