《洞天语录》曰∶高上元君始在尘世而流传大道，引喻天地升降之宜、日月往来之数，而曰内丹。广
成子教黄帝根据法行，持久不见功。乃于崆峒山中，凡以内事为法则，以金石相配合，而曰外丹。内
之丹药，乃为真药，外之丹药，止可疗治病，安乐而已。内丹小则长生不老，大则超凡入圣。始乎二
气交，而凝结在丹田，变精为汞，变汞为砂，砂变为丹，形若弹丸，色同朱橘，而真气自生。以气炼
气，气合神聚而入道，道成而入圣。圣则大而化之，无所不通，岂外丹之可比耶？故知真药、真丹，
身外无求。
《西山记》曰∶以龙交虎媾，结成玄珠；火候无差，烧成大药。真气始生，升之可以炼形，不
避寒暑之患。真气既聚，纳之可以还丹，永除饥渴之苦。于己也岂非药乎？及夫真气施于人也，亦有
验矣。入水水沸，吹木木荣，变苦为甘，改
衰为壮。即人以疗疾苦，无不痊瘥。凝神以祛鬼魅，无不灵应。盖内真而外应也，岂非谓人之药乎？
或以内事不修，真元不识，惟以外之无精金石，加日添火，饵之以求超升，误矣！然而古今上士，亦论
外丹，非外丹不可用。如广成子以朱砂为丹，炼之九转而曰神丹。陈七子以七宝丹砂，炼之九转而曰
灵丹。刘安王以童子小便，炼之七转而曰还丹。是知灵聚而为神，神散而为虚，以气还元，而曰还丹。
后人用之，亦见有功。升仙者，盖始也炼之，而内事兼修，内外俱成，得通仙道。若以外药独用，
气弱神衰，天地秀气不能停留，反为害不细矣。
《洞天语录》说：高上元君起初在尘世流传大道，引用天地升降的适宜规律、日月往来的数理，称之为内丹。广成子教导黄帝依据法则修行，持久练习却不见功效。于是他在崆峒山中，凡是以内部事务为法则，以金石相互配合，称之为外丹。内部的丹药，才是真药；外部的丹药，只能治疗疾病，求得安乐罢了。内丹小则能长生不老，大则能超凡入圣。起始于二气交合，而在丹田凝结，将精转化为汞，将汞转化为砂，砂转化为丹，形状像弹丸，颜色如同朱橘，而真气自然产生。用气来炼化气，气与神聚合而入道，道成就而入圣。圣人则广大而化之，无所不通，哪里是外丹可以比拟的呢？因此知道真药、真丹，身外无需寻求。
《西山记》说：以龙交配虎媾，结成玄珠；火候没有差错，烧炼成大药。真气开始产生，提升它可以炼化形体，不躲避寒暑的祸患。真气既已聚集，收纳它可以返还为丹，永远消除饥渴的痛苦。对于自身来说，难道不是药吗？等到真气施加于人身上，也有验证了。进入水中水会沸腾，吹向树木树木茂盛，变苦为甜，改衰为壮。即使用人来治疗疾苦，没有不痊愈的。凝聚心神以驱除鬼魅，没有不灵验的。大概是因为内部真实而外部相应，这难道不是所说的人的药吗？有人因为不修养内部事务，不认识真元，只以外部的无精金石，添加日光和火焰，服用它以求超脱升仙，这是错误的！然而古今的高士，也谈论外丹，并非外丹不可用。比如广成子用朱砂为丹，炼之九转而称为神丹。陈七子用七宝丹砂，炼之九转而称为灵丹。刘安王用童子小便，炼之七转而称为还丹。由此可知灵气聚拢成为神，神散开成为虚，用气回归元气，称为还丹。后人使用它，也见到功效。升仙的人，大概是开始时炼制药剂，同时修养内部事务，内外都成就，得以通晓仙道。如果单独使用外药，气弱神衰，天地的秀气不能停留，反而造成的危害不小了。
The *Dongtian Yulu* (Record of the Caves and Springs) states: When Gao Shang Yuan Jun (High Supreme Prime Sovereign) first propagated the Great Dao in the mortal world, he drew analogies from the appropriate laws of heaven and earth's ascending and descending, and the numerical cycles of the sun and moon's往来 (intercourse), calling it Neidan (Internal Alchemy). Guangcheng Zi taught the Yellow Emperor to practice according to these methods, but despite persistent effort, no efficacy was seen. Thus, in the Kongtong Mountains, relying on internal affairs as the principle and combining minerals and metals, he called it Waidan (External Alchemy). The alchemical pills within are true medicine; those without can only treat diseases and bring about peace and comfort. Neidan, on a small scale, leads to longevity and freedom from aging; on a large scale, it allows one to transcend the ordinary and enter sainthood. It begins with the interaction of two qi (vital energies), condensing in the Dantian (Elixir Field), transforming Jing (Essence) into Mercury, Mercury into Cinnabar grain, and Cinnabar grain into the Elixir. Its shape resembles a bullet, its color like a vermilion tangerine, and true qi arises spontaneously. Refining qi with qi, qi and Shen (Spirit) gather to enter the Dao; when the Dao is accomplished, one enters sainthood. The sage becomes vast and transformative, penetrating all things—how could this be compared to Waidan? Therefore, knowing that true medicine and true elixir exist, there is no need to seek them outside the body.
The *Xishan Ji* (Record of Western Mountain) states: By the coupling of Dragon and Tiger, the Mysterious Pearl is formed; with precise Huohou (Fire Timing), the Great Medicine is refined. When Zhenqi (True Qi) begins to arise, elevating it can refine the form, avoiding the perils of cold and heat. Once Zhenqi has gathered, containing it can return it to the Elixir, permanently eliminating the suffering of hunger and thirst. Is this not medicine for oneself? When Zhenqi is applied to others, there are also verifications. Entering water causes it to boil; blowing on trees makes them flourish; bitterness turns to sweetness; decline transforms into strength. Using it to treat illnesses, there is no case that does not recover. Concentrating Shen to dispel demons, there is no instance that is not effective. This is because the internal truth corresponds externally—is this not what is meant by "medicine of man"? Some, failing to cultivate internal affairs and unaware of their True Yuan (Original Essence), rely solely on impure minerals and metals, adding sunlight and fire, ingesting them seeking transcendence and ascension; this is an error! However, superior scholars of ancient and modern times also discuss Waidan, asserting that Waidan is not unusable. For example, Guangcheng Zi used Zhusha (Cinnabar) as the elixir, refining it through nine transformations to call it Shendan (Divine Elixir). Chen Qizi used Seven-Treasure Cinnabar, refining it through nine transformations to call it Lingdan (Spiritual Elixir). Liu An Wang used urine from young boys, refining it through seven transformations to call it Huan Dan (Returning Elixir). From this we know that Ling (Spiritual Energy) gathers to become Shen; Shen scatters to become Void. Returning Yuan through Qi is called Huan Dan. Later generations using it have also seen efficacy. Those who ascend to immortality generally began by refining medicines while simultaneously cultivating internal affairs, achieving both internal and external perfection, thereby gaining access to the path of immortality. If Waidan medicine is used alone, Qi becomes weak and Shen declines; the exquisite Qi of heaven and earth cannot remain, causing harm that is not insignificant.