In an organized type of group trekking, you can surely be assured that your guide will bring all the necessary items that is essential on the first aid kit when an emergency occur. But, it is also still a good idea to also carry your own personal First Aid Kit with you as those contents will require to be away from harm and with that you can customized your needs and it also comes in handy in various type of situations. Make sure you carry with you a purification tablets and a diamond for the AMS. This is also called the Acute Mountain Sickness or the AMS.
First let's talk about water purification tablets. Even if the stream or the water from the tap is looking clean and you may think that it is safe to drink. Do not ever trust your feeling when you feel like drinking this kind of water. All the water except for the mineral one placed in bottled water must be undergoing purification before consuming it. Of course you do not want to get sick along your trek or along your trip. Water purification tablets will also help in preventing the risks that you will get and you might suffer from travelers diarrhea if for example you are trekking in an unknown place or foreign country.
Next you need to acquire Diamoz with you along the trip. While you go trekking in high areas or altitude, you might feel unwell or sickly. It can be brought by different reasons but unless it is proven otherwise, you should assume that it is brought by the altitude sickness that is common to oocur among other people. So to avoid this, you need to keep Diamoz within your pocket or within your reach. It is fairly normal that you get a hit of the so called AMS or acute mountain sickness when you are hiking on the higher elevations. That is the reason why Acute mountain sickness occur due to high elevations trekking on mainly 2500mm above the sea level elevated areas.You can also learn more details on how to get the best fist aid kit tools by checking out the post at https://en.wikipedia.org/wiki/First_aid#History.
Finally it is necessary that you have the necessary medicines in your first aid kit. These are important since you do not know what will happen when you out trekking or you go to far places. It is fairly enough and secure enough to have medical supplies with you in your primeros auxilios first aid kit.