Mṛta sañjīvana mantra मृत सञ्जीवन मन्त्र  (Ṛg Veda X.161. 1-5)

मुञ्चामि त्वा हविषा जीवनाय कमज्ञातक्ष्मादुत राजयक्ष्मात्।
ग्राहिर्जग्राह यदि वैतदेनं तस्या इन्द्राग्नी प्र मुमुक्तमेनम्॥ १

यदि क्षितायुर्यादि वा परेतो यदि मृत्योरन्तिकं नीत एव।
तमा हरामी निरृतेरुपस्थादस्पार्षमेनं शतशारदाय॥ २

सहस्राक्षेण शतशारदेन शतायुषा हविषाहार्षमेनम्।
शतं यथेमं शरदो नयातीन्द्रो विक्ष्वस्य दुरितस्य पारम्॥ ३

शतं जीव शरदो वर्धमानः शतं हेमन्ताञ्छतमु वसन्तान्।
शतमिन्द्राग्नी सविता बृहस्पतिः शतायुषा हविषेमं पुनर्दुः॥ ४

आहार्षं त्वाविदं त्वा पुनरागाः पुनर्नव।
सर्वाङ्ग सर्वं ते  चक्षुः सर्वमायुश्च तेऽविदम्॥ ५

muñcāmi tvā haviṣā jīvanāya kamajñātakṣmāduta rājayakṣmāt |
grāhirjagrāha yadi vaitadenaṁ tasyā indrāgnī pra mumuktamenam || (1)

yadi kṣitāyuryādi vā pareto yadi mṛtyorantikaṁ nīta eva |
tamā harāmī nirṛiterupasthādaspārṣamenaṁ śataśāradāya || (2)

sahasrākṣeṇa śataśāradena śatāyuṣā haviṣāhārṣamenam |
śataṁ yathemaṁ śarado nayātīndro vikṣvasya duritasya pāram || (3)

śataṁ jīva śarado vardhamānaḥ śataṁ hemantāñchatamu vasantān |
śatamindrāgnī savitā bṛhaspatiḥ śatāyuṣā haviṣemaṁ punarduḥ || (4)

āhārṣaṁ tvāvidaṁ tvā punarāgāḥ punarnava |
sarvāṅga sarvaṁ te  cakṣuḥ sarvamāyuśca te'vidam || (5)

With compound Sanskrit words divided:

muñcāmi tvā haviṣā jīvanāya kam ajñātakṣmāduta rājayakṣmāt |
grāhir jagrāha yadi vaitad enaṁ tasyā indrāgnī pra mumuktam enam || (1)

yadi kṣitāyur yādi vā pareto yadi mṛtyor antikaṁ nīta eva |
tam ā harāmī nirṛiter upasthād aspārṣam enaṁ śataśāradāya || (2)

sahasrākṣeṇa śataśāradena śatāyuṣā haviṣāhārṣam enam |
śataṁ yathemaṁ śarado nayātīndro vikṣvasya duritasya pāram || (3)

śataṁ jīva śarado vardhamānaḥ śataṁ hemantāñ chatam u vasantān |
śatam indrāgnī savitā bṛhaspatiḥ śatāyuṣā haviṣemaṁ punar duḥ || (4)

āhārṣaṁ tvāvidaṁ tvā punar āgāḥ punarnava |
sarvāṅga sarvaṁ te  cakṣuḥ sarvamāyuś ca te 'vidam || (5)

Meaning of Mrita Sanjivini Mantra:

By means of the oblation, I set you (O patient), free to live safe from undeveloped consumption and from royal consumption; and if the seizer (the consumption) has already seized (the patient), then you, O resplendent Lord and fire-divine, set him free. (1)

If he (the patient) be of wasted life, or already dead, or he lies to the verge of death, I shall try to bring him back from the lap of Probability. I make him strong enough to live for a hundred years. (2)

I have rescued him with an oblation having a thousand eyes, conferring a hundred years, giving life for a century, so that the Lord of resplendence may conduct him beyond all harm for a hundred years (3)

Regaining your strength, O patient, live for a hundred autumns, a hundred winters, a hundred springs; may the sun, fire-divine, creator and universal God, propitiated by this century-yielding oblation, give this man back to us for a hundred years. (4)

I have rescued you, O patient, I have found you; come back again; yes, now you are young again, quite sound in body; I have obtained for you all your senses, your whole life. (5)

Other Important articles:

Mrityunjaya Mantra

Mantra For Curing Ailments

Rakshoghna Mantra